Remove /ok-to-test bot message since it's deprecated

[iholder101]

What happened:
Today, when a non-community member submits a PR, the bot posts the following comment:

Hi @member. Thanks for your PR.

PRs from untrusted users cannot be marked as trusted with /ok-to-test in this repo meaning untrusted PR authors can never trigger tests themselves. Collaborators can still trigger tests on the PR using /test all.

I understand the commands that are listed here.

What you expected to happen:
Since the /ok-to-test label is deprecated and no longer works, so the bot should avoid such comments.

How to reproduce it (as minimally and precisely as possible):
non-community member to submit a PR

Additional context:
Example: kubevirt/kubevirt#11743 (comment)

[iholder101]

FYI @dhiller @oshoval @brianmcarey

[oshoval]

I would say update the comment to reflect the current state
but it might depend if it is internal plugin and then we need to fork test-infra (unless we are doing it already)
and then it might be too much for just this change

[kubevirt-bot]

Issues go stale after 90d of inactivity.
Mark the issue as fresh with /remove-lifecycle stale.
Stale issues rot after an additional 30d of inactivity and eventually close.

If this issue is safe to close now please do so with /close.

/lifecycle stale

[kubevirt-bot]

Stale issues rot after 30d of inactivity.
Mark the issue as fresh with /remove-lifecycle rotten.
Rotten issues close after an additional 30d of inactivity.

If this issue is safe to close now please do so with /close.

/lifecycle rotten

[iholder101]

/remove-lifecycle rotten